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Observed and predicted shelf slope, Eel River, CA
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Upscaling Simple Models for Energetic Shelf Sediment Transport, Marine Geosciences Program. C.T. Friedrichs, Principal Investigator
Proposed Tasks:
Results of realistic turbulence closure models will be upscaled to produce simple analytical expressions for energetic sediment transport. I will apply a wave-resolving (i.e., very short time-step), one-dimensional (highly resolved in z) numerical model with advanced turbulence closure to simulate energetic suspensions of both mud and sand. The numerical simulations will be used to extend my recently derived analytical expressions for fluid mud suspensions towards coarser sediment and reconcile expressions for highly energetic fluid mud and plane bed sand suspensions. For both mud and sand it is anticipated that the shut down of turbulence by stable stratification will play a critical role in determining the maximum possible sediment load for a given energy level.
Analytical relations for energetic sediment transport will, in turn, be upscaled to derive simple expressions for equilibrium shelf profiles and associated deposits. My initial results of upscaling wave-supported gravity flows indicate that the slope of resulting clinoforms increase with greater sediment supply and smaller wave height. For sandier environments, it is anticipated that onshore transport by wave asymmetry will balance offshore transport by gravity. My preliminary results of upscaling sand transport suggest that concave upward equilibrium shorefaces become steeper as wave height decreases, grain size increases or wave period increases. The above results of upscaling transport relations to derive shelf profiles will be compared to global data bases of shelf morphology and also to the output of other numerical models of margin evolution.
February 2003 Model Description Questionaire - Download (PDF 140K)
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